Battery charger

[chrisf1]

Hi again everyone I realise the site does not specialise in battery chargers but to be quite honest I could not find anywhere else to ask my questions I am at the moment bidding on Gumtree for 2 workshop type 12/24volt battery chargers that have start engine option as well they are both advertised spares or repair sold as not working one is a Sealey super start 620 the other is a similar sort of thing by MAC tools both are on wheels and look in generally rough condition but thanks to Mr Gordon Browns legacy to us, my budget is extremely tight so I have no choice but go this route, please bear in mind I am only feeling the water at the moment but is there much to go wrong in these type of chargers are they not just transformers. Would it be possible to tell by looking if a transformer has burnt out, as you have probably gathered by now I have little knowledge of electrickery apart from you can't see it or smell it and it still bites, my thinking was with the Sealey give it to one of there service centres and get a quote for repair and the MAC tools one the same, they appear to give themselves a good write up but they would anyway, does anyone have an unbiased opinion of them or in fact any knowledge of them at all The upshot of this is a gamble really, make one work if need be with parts from the other or if the quote for repair is not outrageous go that route any advice welcome thanks Chris

 

[Robotstar5]

Unless it's something simple like a blown fuse (why?) or a wire come off, I suspect the suppliers will charge the best part of the cost of a new one with today's labour rates.
If you do get them I'm sure a few photo's and simple tests will get you some help on here.

 

[the snooper]

unless they the automatic type chargers i would imagine they will be transformer and rectifier and possibly a small circuit to measure output if if they use led's could be as simple as a broken mains lead if they are cheap have a go

 

[scarecrow]

if the transformer is shorted on the primary side it will pop the main trips and not too sure about the secondary winding maybe one of the Sparky's can enlighten you. other than that there's not too much to more wrong in a charger except the rectifier take a voltmeter with you and check the output

 

[madkayaker]

if the secondary side was shorted it would produce a overload that would trip the main trip

 

[rtbcomp]

A secondary or primary short could trip an MCB, a primary short could trip an RCD as well.

 

[SirDick Diodenob esquire]

If you are on a really tight budget use your mig welder to start your cars and give a fast charge to a flat battery , you just need to make sure the mig output voltage isnt over about 16 V open circuit and use a switch/switches to close the contactor and open the motor circuit whilst its in this mode . The mig output is not ideal for starting and with some there would be a risk of melting the transformer or blowing the rectifier or even damaging the car but my thermal arc 180 mig works almost as well as a purpose made boost/starter and only cost £60 so not much risk for me . I dont know if I would risk a more expensive machine doing this . A non working boost/starter charger is worth a £20 punt they are similar to a mig welder but without the motor and choke so less complicated , if the transformer has gone then its probably not worth fixing and as already said dont take it to a service centre , will certainly cost more than its value to get it fixed that way .